In favor of vitrectomy
Dr. Landers said there is considerable evidence that PPV reduces macular edema in patients with DME. In the DRCR.net Vitrectomy for DME study, central subfield thickness (CST) decreased in more than 90% of patients and was reduced 33% overall, from 412 µm to 278 µm.
Furthermore, in a 2013 publication that reviewed data from more than 1,800 patients with DME, Dr. Landers and colleagues found the vast majority of patients achieved a durable decrease in macular thickness, showing persistence through follow-up periods that extended up to 30 months.
Doubt that PPV has benefit for treating DME may exist because in the DRCR.net Vitrectomy for DME study, it was not associated with improvement in visual acuity. Dr. Landers suggested, however, that selection bias may explain that study’s outcome.
“We know from other studies that vision of patients with DME never improves without an associated decrease in CST,” Dr. Landers said. “The DRCR.net study, however, recruited patients who had failed all other treatments and they likely had irreversible retinal damage that limited their potential for vision improvement even after successful reduction of their macular edema.”